Relapse to drug and food seeking presents a significant public health concern as excessive preoccupation with drug or food seeking and taking contributes to numerous negative health outcomes. Using a rat model of reward seeking, this application aims to identify gene expression patterns in the brains of rats with a history of sucrose self-administration under short or long-term abstinence conditions known to produce low or high levels, respectively, of reward seeking ("incubation of craving"). In addition, some rats will experience abstinence in an enriched environment, a manipulation we have previously demonstrated to attenuate incubation of sucrose seeking. Gene expression will be visualized in the first Aim using Fos immunohistochemistry to map sucrose-cue activated regions. Aim 2 will utilize this mapping information to focus on discrete brain regions to isolate and quantitate dopamine D1 receptor signal cascade proteins, some in basal vs. phosphorylated states, as we have found that D1 receptor antagonism has time-dependent (incubation-dependent) effects on sucrose seeking. Beyond the goal of identifying neural substrates of addiction as a means to informing novel addiction therapies, the studies will be conducted as a means to expose undergraduate researchers to the scientific process. Engaging the students in this way will enhance their training experiences and the research environment at Western Washington University. PUBLIC HEALTH RELEVANCE: Relapse to drug or food seeking presents a significant public health concern as excessive preoccupation with, and consumption of, drugs and food contribute to numerous negative health outcomes. The proposed studies aim to identify differential gene expression in the brains of rats related to relapse behavior with or without the relapse-attenuating pre-treatment of extended enriched environment living conditions. The results of these studies may lead to a better understanding of the molecular biology of relapse behavior and thus facilitate development of novel relapse treatment approaches.